Radioactive charging device



8- 7, 1956 R- R. ANNIS ET AL 2,758,225

RADIOACTIVE CHARGING DEVICE Fild Au 18, 1952 RRDIOQCTIVE 3 TA PARTICLE EMITTING MATERIAL INVENTOR. RICHARD R. ANNIS HOWARD HASELKORN BY ATTORNEY United States Patent 2,758,225: RADIOACTIVE CHARGING DEVICE Richard R. Annis, Colebrook, N. H and Howard Haselkom, Asbury Park, N. J.

Application Augustlfl, 1952,,Serial No. 305,101 2 Claims. (Cl. 310-3) (Granted under Title 35, U. S. Code (1952); sec. 266) The invention described herein may be manufactured and used by and for the Government for governmental purposes without payment of any royalty thereon.

This invention relates to batteries and more. particularly to a radioactive battery wherein a potential is. set up between metals having different work functions.

It is an object of the present invention to provide a battery of long shelf life.

It is a further object to provide, a battery of long life that is relatively compact and. contains substantially no moving parts.

It is another object to provide a battery of long lifethat requires a minimum of maintenance.

In accordance with the present invention, there is provided a battery wherein a potential is set up between metals having different work functions. It comprises a gas filled chamber having confined therein a plurality of spaced metallic units. Each of said units comprises intimately united first and second metals having different work functions and the units are so aligned that the opposing metals forming the bounds between any two adjacent units are metals having different work functions. Non-conducting spacing means are provided between the metallic units and means are provided within the chamber for ionizing the gas contained therein whereby a current is made to flow between adjacent units.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

In the drawings, Fig. l is an outline view of a radioactive battery in accordance with a preferred embodiment of the invention. Fig. 2 is a perspective view partially cut away. Fig. 3 is a section taken along line 33 of Fig. 1. Fig. 4 is a section taken along line 44 of Fig. 3 looking in the direction of the arrows. Fig. 5 is a section taken along line 55 of Fig. 3 looking in the direction of the arrows and Fig. 6 is an enlarged cross-section of the spaced metallic units.

Referring now more particularly to the drawings, in Fig. 1 there is shown an outline view of a gas-filled radioactive battery 8 comprising a body portion 10 terminated by end walls 9 and 11, a gas inlet 12 and terminal elements 14 and 16. The body portion 10, end walls 9 and 11, and gas inlet 12 are comprised of Lucite and terminal elements 14 and 16 are of a suitable metal.

In Fig. 2, there is shown a perspective view of battery 8 partially cut away showing a Lucite frame 18 extending longitudinally within battery 8 and comprising four planar sheets disposed in quadrature to divide the interior of said battery into quadrants 20, 22, 24, and 26. As shown in Fig. 3, frame 18 is provided with end portions 28 and 29. Within each of said quadrants, there is provided a bank of uniformly spaced longitudinally arranged metallic units such as 30 which are supported at one end by end portion 29. The other ends of said banks are in abutting contact with discrete contact studs 32, 33, 34,

Patented Aug. 7, 1956 and 35 extending through end portion 28. Stud 32 in contact with metallic unit bank in quadrant 26 and stud 34 in contact with metallic unit bank in quadrant 22 are electrically connected to terminal elements 14 and 16 respectively by wires 36 and 38. Metallic unit banks are connected in series by wire 42 which connects studs 33 and 35 and by connecting wires 44 and 46. Within battery 8 there is provided a beta particle emitting radioactive source 40 of relatively long half life such as strontium or thallium 204 coated on the inner surfaces of the walls of body portion 10 between end portions 28 and 29. Said beta particle emitting radioactive source is insulated from the. metallic unit-s 30 by a. suitable thin plastic coating 41. Outlet hole 43 is provided in end wall, 9 for purging gas when chamber is filled therewith and Lucite disc 45 serves as a sealing cap when battery is. operating. Notches as at 39 are provided in end portions 28 and 29 to permit free diffusion of gas throughout, interior of body portion 10.

Fig. 6 shows an enlarged cross-section of a metallic unit. comprising an aluminum layer 48,. a zinc layer 50, and. a. brass layer 52. It is to be understood, of course, that copper, a copper alloy, or metal or alloy having high work function arev suitable. Non-conducting spacers madev of Lucite or other suitable insulating material as shown at 54 are provided to maintain said metallic units a predetermined distance from each other.

Referring to the operation of said battery, since there is a difference in potential between the opposing spaced metals, aluminum and brass, due to their different work functions, a current can be made to fiow between said spaced dissimilar metals if an ionized gas atmosphere is provided. This atmosphere is provided by filling said battery with an inert gas such as Xenon or other relatively inert gas and coating the inner walls of the battery with a radioactive material of relatively long half-life such as strontium 90 or thallium 204 as explained above. The basic cell in this battery consists of two dissimilar metals having a contact potential between them due to their difference in work function. By connecting many of these cells in series, the total battery voltage may be a linear function of the number of cells connected in series. The ionized gas atmosphere enables a current to flow between said dissimilar metals. The voltage of the battery can be varied by tapping off different portions of the battery.

Although the difference in potential between opposing, spaced, dissimilar metals due to their different work functions has been advanced as the basis for the operation of the radioactive battery, it is not to be inferred that other theories of operation are not applicable nor should it be inferred that the operativeness of this invention is dependent upon the above set forth theory of operation.

It has been found that optimum results are obtained by using a metal of high work function such as platinum, gold, copper, or a copper alloy and one of low work function, such as aluminum. Since copper or copper alloys are relatively inexpensive as compared to platinum and gold, the best combination of metals to use is copper and aluminum. The metallic unit used in the preferred embodiment of this invention consists of a layer of aluminum and a layer of brass with a layer of zinc interposed therebetween since brass cannot be efficiently plated directly upon aluminum.

It has also been found that the area of the opposing metal surfaces and the distance between them are factors in obtaining optimum results as the output current varies directly with said area and an optimum distance between metals exists because of recombination, saturation and volume effects. This distance may vary between 0.025 inch and 0.075 inch. The best distance is found to be about 0.050 inch. The gas used in the battery is preferably one of the inert gases such as xenon. However, gases such as nitrogen and other suitable inert gases well known in the art may be used. The radioactive source should be one of long half-life, be relatively inexpensive and have great ionizing power. Strontium 90 and thallium 204 are beta particle emitting radioactive metals having such properties.

It is obvious that the battery which is the present invention has many advantages. Its life depends. only upon the half-life of the radioactive-source and the adsorption of gas. It is compact and'mechanically free having very few moving parts. It canbe made cheaply and its maintenance requirements are negligible.

While there has been described what is at present considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is: i

1. A radioactive battery wherein a potential is set up between metals of different work function comprising a chamber defined by a plurality of walls, said chamber containing a gas selected from the group consisting of the inert gases and nitrogen, a plurality of metallic unit banks disposed in parallel relationship confined within said chamber, means insulating said metallic unit banks from each other, each bank comprising spaced metallic units, each of said units being spaced 0.025 to 0.075 inch from each other and comprising successively intimately united layers of aluminum, zinc, and brass, each of said units being so aligned that the opposing metals forming the bonds between any two adjacent units are aluminum and brass, spacers of insulating material between said units, radioactive beta particle emitting means on the walls of said chamber whereby a current is made to flow between said units, means for electrically connecting said banks so that the internal voltage of said battery is the series ad dition of all said potentials, and terminal elements operatively associated with said metallic units for connection to an external circuit.

2. A radioactive battery as in claim 1 wherein said radioactive beta particle emitting means is present as a coating on the inner walls of said chamber.

1919, by Stanford University Press, pp. 89 to 94. 

1. A RADIOACTIVE BATTERY WHEREIN A POTENTIAL IS SET UP BETWEEN METALS OF DIFFERENT WORK FUNCTION COMPRISING A CHAMBER DEFINED BY A PLURALITY OF WALLS, SAID CHAMBER CONTAINING A GAS SELECTED FROM THE GROUP CONSISTING OF THE INERT GASES AND NITRGEN, A PLURALITY OF METALLIC UNIT BANKS DISPSED IN PARALLEL RELATIONSHIP CONFINED WITHIN SAID CHAMBER, MEANS INSULATING SAID METALLIC UNIT BANKS FROM EACH OTHER, EACH BANK COMPRISING SPACED METALLIC UNITS, EACH OF SAID UNITS BEING SPACED 0.025 T 0.075 INCH FROM EACH OTHER AND COMPRISING SUCCESSIVELY INTIMATELY UNITED LAYERS OF ALUMINUM, ZINC, AND BRASS, EACH OF SAID UNITS BEING SO ALIGNED THAT THE OPPOSING METALS FORMING THE BONDS BETWEEN ANY TWO ADJACENT UNITS ARE ALUMINUM AND BRASS, 